Abstract:

A digital broadcasting system and a data processing method are disclosed.
A receiving system of the digital broadcasting system includes a
receiving unit, an SI handler, and a decoding unit. The receiving unit
receives broadcast signals including mobile service data and main service
data. Herein, the mobile service data may configure a data group, and the
data group may include a signaling information region in some of a
plurality of data regions. Also, the signaling information region may
include TPC signaling data and FIC signaling data. The SI handler
acquires channel configuration information of the mobile service data
from the broadcast signal using pre-decided IP access information, and
extracts encoding format information for each IP stream component within
a corresponding virtual channel service RTP-packetized and received from
the acquired channel configuration information. The decoding unit decodes
the mobile service data of the corresponding IP stream component based
upon the extracted encoding format information.

Claims:

1-15. (canceled)

16. A method of transmitting a broadcast signal in a transmitter, the
method comprising:transmitting a transmission frame including a plurality
of slots during which data groups of mobile data are transmitted, the
mobile data being encoded through a Reed-Solomon (RS) frame, each data
group including a plurality of regions, each region including a plurality
of data blocks, each data block including contiguous data
segments,wherein first and second regions in each data group include at
least three known data sequences which are spaced apart by regular data
segments, and the first region further includes signaling information of
the mobile data in specified data segments,wherein the signaling
information includes first channel information providing binding
information between a mobile service identifier and an ensemble being a
collection of services of the mobile data, and second channel information
describing the transmission frame and the data groups,wherein the
ensemble includes a service map table (SMT) providing IP address
information for a service, and wherein the service includes a mobile
service component and the SMT includes an encoding parameter identifying
an encoding format of the mobile service component.

17. The method of claim 16, wherein a value of the encoding format
represents a payload type of a Real-time Transport Protocol (RTP) stream.

18. The method of claim 16, wherein the SMT further includes an identifier
of the ensemble.

19. The method of claim 18, wherein the second channel information
includes an identifier of a parade which is a collection of the data
groups.

20. The method of claim 19, wherein the identifier of a parade is bits
generated by adding an additional bit to the identifier of the ensemble.

21. The method of claim 20, wherein the additional bit is determined by a
type of the ensemble.

22. A method of receiving a broadcast signal in a receiver, the method
comprising:receiving a transmission frame including a plurality of slots
during which data groups of mobile data are received, the mobile data
being data encoded through a Reed-Solomon (RS) frame, each data group
including a plurality of regions, each region including a plurality of
data blocks, each data block including contiguous data segments,wherein
first and second regions in each data group include known data sequences
which are spaced regular data segments apart, and the first region
further includes a known data sequence and signaling information of the
mobile data in specified data segments,wherein the signaling information
includes first channel information providing binding information between
a mobile service identifier and an ensemble being a collection of
services of the mobile data, and second channel information describing
the transmission frame and the data groups,wherein the ensemble includes
a service map table (SMT) providing IP address information for a service,
andwherein the service includes a mobile service component, and the SMT
includes an encoding parameter identifying an encoding format of the
mobile service component;building the RS frame using the data groups
included in the transmission frame; anddecoding the RS frame.

23. The method of claim 22, wherein a value of the encoding format
represents a payload type of a Real-time Transport Protocol (RTP) stream.

24. The method of claim 22, wherein the SMT further includes an identifier
of the ensemble.

25. The method of claim 24, wherein the second channel information
includes an identifier of a parade which is a collection of the data
groups.

26. The method of claim 25, wherein the identifier of a parade is bits
generated by adding an additional bit to the identifier of the ensemble.

27. The method of claim 26, wherein the additional bit is determined by a
type of the ensemble.

[0003]The present invention relates to a digital broadcasting system and a
method of processing data in a digital broadcasting system for
transmitting and receiving digital broadcast signals.

[0004]2. Discussion of the Related Art

[0005]The Vestigial Sideband (VSB) transmission mode, which is adopted as
the standard for digital broadcasting in North America and the Republic
of Korea, is a system using a single carrier method. Therefore, the
receiving performance of the digital broadcast receiving system may be
deteriorated in a poor channel environment. Particularly, since
resistance to changes in channels and noise is more highly required when
using portable and/or mobile broadcast receivers, the receiving
performance may be even more deteriorated when transmitting mobile
service data by the VSB transmission mode.

SUMMARY OF THE INVENTION

[0006]Accordingly, an object of the present invention is to provide a
digital broadcasting system and a data processing method that are highly
resistant to channel changes and noise.

[0007]Another object of the present invention is to provide a receiving
system and a data processing method that can receive and process encoding
format information of an IP stream component, which is RTP packetized and
received.

[0008]To achieve these objects and other advantages and in accordance with
the purpose of the invention, as embodied and broadly described herein, a
receiving system includes a receiving unit, a system information (SI)
handler, and a decoding unit. The receiving unit receives broadcast
signals including mobile service data and main service data. Herein, the
mobile service data may configure a data group, and the data group may
include a signaling information region in some of a plurality of data
regions. Also, the signaling information region may include transmission
parameter channel (TPC) signaling data and fast information channel (FIC)
signaling data. The system information (SI) handler acquires channel
configuration information of the mobile service data from the broadcast
signal using pre-decided internet protocol (IP) access information, and
extracts encoding format information for each IP stream component within
a corresponding virtual channel service real-time transport protocol
(RTP)-packetized and received from the acquired channel configuration
information. The decoding unit decodes the mobile service data of the
corresponding IP stream component based upon the extracted encoding
format information.

[0009]Additionally, the receiving unit may further include a known
sequence detector detecting a known data sequence included in the data
group. And, herein, the detected known data sequence may be used for
demodulating and channel-equalizing the mobile service data. The
receiving unit may refer to the fast information channel (FIC) signaling
data so as to only acquire slots including data groups requested to be
received using a time-slicing method. The channel configuration
information may correspond to a service map table (SMT). Herein, the
encoding format information may be included in the SMT in any one of a
field format and a descriptor format, thereby being received.

[0010]When an RTP_payload_type field included in the SMT is assigned with
a value within a first value range, the SI handler may extract a
pre-stored encoding format information respective of the RTP_payload_type
value. On the other hand, when an RTP_payload_type included in the SMT is
assigned with a value within a second value range, the SI handler may
parse the RTP_payload_descriptor matching the RTP_payload_type value from
the SMT, so as to extract the encoding format information of the
corresponding IP stream component. The encoding format information may be
included in the RTP payload descriptor as a MIME type.

[0011]In another aspect of the present invention, a method for processing
data in a digital broadcast receiving system includes receiving broadcast
signals including mobile service data and main service data, wherein the
mobile service data configure a data group, wherein the data group
includes a signaling information region in some of a plurality of data
regions, and wherein the signaling information region includes
transmission parameter channel (TPC) signaling data and fast information
channel (FIC) signaling data, acquiring channel configuration information
of the mobile service data from the broadcast signal using pre-decided
internet protocol (IP) access information, and extracting encoding format
information for each IP stream component within a corresponding virtual
channel service real-time transport protocol (RTP)-packetized and
received from the acquired channel configuration information, and
decoding the mobile service data of the corresponding IP stream component
based upon the extracted encoding format information.

[0012]Additional advantages, objects, and features of the invention may be
realized and attained by the structure particularly pointed out in the
written description as well as the appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 illustrates a block diagram showing a general structure of a
digital broadcasting receiving system according to an embodiment of the
present invention;

[0014]FIG. 2 illustrates an exemplary structure of a data group according
to the present invention;

[0015]FIG. 3 illustrates an RS frame according to an embodiment of the
present invention;

[0016]FIG. 4 illustrates an example of an MH frame structure for
transmitting and receiving mobile service data according to the present
invention;

[0017]FIG. 5 illustrates an example of a general VSB frame structure;

[0018]FIG. 6 illustrates a example of mapping positions of the first 4
slots of a sub-frame in a spatial area with respect to a VSB frame;

[0019]FIG. 7 illustrates a example of mapping positions of the first 4
slots of a sub-frame in a chronological (or time) area with respect to a
VSB frame;

[0020]FIG. 8 illustrates an exemplary order of data groups being assigned
to one of 5 sub-frames configuring an MH frame according to the present
invention;

[0021]FIG. 9 illustrates an example of a single parade being assigned to
an MH frame according to the present invention;

[0022]FIG. 10 illustrates an example of 3 parades being assigned to an MH
frame according to the present invention;

[0023]FIG. 11 illustrates an example of the process of assigning 3 parades
shown in FIG. 10 being expanded to 5 sub-frames within an MH frame;

[0024]FIG. 12 illustrates a data transmission structure according to an
embodiment of the present invention, wherein signaling data are included
in a data group so as to be transmitted;

[0025]FIG. 13 illustrates a hierarchical signaling structure according to
an embodiment of the present invention;

[0026]FIG. 14 illustrates an exemplary FIC body format according to an
embodiment of the present invention;

[0027]FIG. 15 illustrates an exemplary bit stream syntax structure with
respect to an FIC segment according to an embodiment of the present
invention;

[0028]FIG. 16 illustrates an exemplary bit stream syntax structure with
respect to a payload of an FIC segment according to the present
invention, when an FIC type field value is equal to `0`;

[0029]FIG. 17 illustrates an exemplary bit stream syntax structure of a
service map table according to the present invention;

[0030]FIG. 18 illustrates an exemplary bit stream syntax structure of an
MH audio descriptor according to the present invention;

[0031]FIG. 19 illustrates an exemplary bit stream syntax structure of an
MH current event descriptor according to the present invention;

[0032]FIG. 20 illustrates an exemplary bit stream syntax structure of an
MH next event descriptor according to the present invention;

[0033]FIG. 21 illustrates an exemplary bit stream syntax structure of an
MH system time descriptor according to the present invention;

[0034]FIG. 22 illustrates segmentation and encapsulation processes of a
service map table according to the present invention;

[0035]FIG. 23 illustrates a flow chart for accessing a virtual channel
using FIC and SMT according to the present invention;

[0036]FIG. 24 illustrates an exemplary bit stream syntax structure of an
MH RTP payload descriptor according to the present invention; and

[0037]FIG. 25 illustrates an exemplary method for accessing an IP stream
component based upon an RTP payload according to an embodiment of the
present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0038]Reference will now be made in detail to the preferred embodiments of
the present invention, examples of which are illustrated in the
accompanying drawings. Hereinafter, the preferred embodiment of the
present invention will be described with reference to the accompanying
drawings. At this time, it is to be understood that the following
detailed description of the present invention illustrated in the drawings
and described with reference to the drawings are exemplary and
explanatory and technical spirits of the present invention and main
features and operation of the present invention will not be limited by
the following detailed description.

DEFINITION OF THE TERMS USED IN THE PRESENT INVENTION

[0039]Although general terms, which are widely used considering functions
in the present invention, have been selected in the present invention,
they may be changed depending on intention of those skilled in the art,
practices, or new technology. Also, in specific case, the applicant may
optionally select the terms. In this case, the meaning of the terms will
be described in detail in the description part of the invention.
Therefore, it is to be understood that the terms should be defined based
upon their meaning not their simple title and the whole description of
the present invention.

[0040]Among the terms used in the description of the present invention,
main service data correspond to data that can be received by a fixed
receiving system and may include audio/video (A/V) data. More
specifically, the main service data may include A/V data of high
definition (HD) or standard definition (SD) levels and may also include
diverse data types required for data broadcasting. Also, the known data
correspond to data pre-known in accordance with a pre-arranged agreement
between the receiving system and the transmitting system.

[0041]Additionally, among the terms used in the present invention, "MH"
corresponds to the initials of "mobile" and "handheld" and represents the
opposite concept of a fixed-type system. Furthermore, the MH service data
may include at least one of mobile service data and handheld service
data, and will also be referred to as "mobile service data" for
simplicity. Herein, the mobile service data not only correspond to MH
service data but may also include any type of service data with mobile or
portable characteristics. Therefore, the mobile service data according to
the present invention are not limited only to the MH service data.

[0042]The above-described mobile service data may correspond to data
having information, such as program execution files, stock information,
and so on, and may also correspond to A/V data. Most particularly, the
mobile service data may correspond to A/V data having lower resolution
and lower data rate as compared to the main service data. For example, if
an A/V codec that is used for a conventional main service corresponds to
a MPEG-2 codec, a MPEG-4 advanced video coding (AVC) or scalable video
coding (SVC) having better image compression efficiency may be used as
the A/V codec for the mobile service. Furthermore, any type of data may
be transmitted as the mobile service data. For example, transport
protocol expert group (TPEG) data for broadcasting real-time
transportation information may be transmitted as the main service data.

[0043]Also, a data service using the mobile service data may include
weather forecast services, traffic information services, stock
information services, viewer participation quiz programs, real-time polls
and surveys, interactive education broadcast programs, gaming services,
services providing information on synopsis, character, background music,
and filming sites of soap operas or series, services providing
information on past match scores and player profiles and achievements,
and services providing information on product information and programs
classified by service, medium, time, and theme enabling purchase orders
to be processed. Herein, the present invention is not limited only to the
services mentioned above.

[0044]In the present invention, the transmitting system provides backward
compatibility in the main service data so as to be received by the
conventional receiving system. Herein, the main service data and the
mobile service data are multiplexed to the same physical channel and then
transmitted.

[0045]Furthermore, the transmitting system according to the present
invention performs additional encoding on the mobile service data and
inserts the data already known by the receiving system and transmitting
system (e.g., known data), thereby transmitting the processed data.

[0046]Therefore, when using the transmitting system according to the
present invention, the receiving system may receive the mobile service
data during a mobile state and may also receive the mobile service data
with stability despite various distortion and noise occurring within the
channel.

[0047]Receiving System

[0048]FIG. 1 illustrates a block diagram showing a general structure of a
receiving system according to an embodiment of the present invention. The
receiving system according to the present invention includes a baseband
processor 100, a management processor 200, and a presentation processor
300.

[0050]The operation controller 110 controls the operation of each block
included in the baseband processor 100.

[0051]By tuning the receiving system to a specific physical channel
frequency, the tuner 120 enables the receiving system to receive main
service data, which correspond to broadcast signals for fixed-type
broadcast receiving systems, and mobile service data, which correspond to
broadcast signals for mobile broadcast receiving systems. At this point,
the tuned frequency of the specific physical channel is down-converted to
an intermediate frequency (IF) signal, thereby being outputted to the
demodulator 130 and the known sequence detector 140. The passband digital
IF signal being outputted from the tuner 120 may only include main
service data, or only include mobile service data, or include both main
service data and mobile service data.

[0052]The demodulator 130 performs self-gain control, carrier recovery,
and timing recovery processes on the passband digital IF signal inputted
from the tuner 120, thereby translating the IF signal to a baseband
signal. Then, the demodulator 130 outputs the baseband signal to the
equalizer 140 and the known sequence detector 150. The demodulator 130
uses the known data symbol sequence inputted from the known sequence
detector 150 during the timing and/or carrier recovery, thereby enhancing
the demodulating performance.

[0053]The equalizer 140 compensates channel-associated distortion included
in the signal demodulated by the demodulator 130. Then, the equalizer 140
outputs the distortion-compensated signal to the block decoder 160. By
using a known data symbol sequence inputted from the known sequence
detector 150, the equalizer 140 may enhance the equalizing performance.
Furthermore, the equalizer 140 may receive feed-back on the decoding
result from the block decoder 160, thereby enhancing the equalizing
performance.

[0054]The known sequence detector 150 detects known data place (or
position) inserted by the transmitting system from the input/output data
(i.e., data prior to being demodulated or data being processed with
partial demodulation). Then, the known sequence detector 150 outputs the
detected known data position information and known data sequence
generated from the detected position information to the demodulator 130
and the equalizer 140. Additionally, in order to allow the block decoder
160 to identify the mobile service data that have been processed with
additional encoding by the transmitting system and the main service data
that have not been processed with any additional encoding, the known
sequence detector 150 outputs such corresponding information to the block
decoder 160.

[0055]If the data channel-equalized by the equalizer 140 and inputted to
the block decoder 160 correspond to data processed with both
block-encoding and trellis-encoding by the transmitting system (i.e.,
data within the RS frame, signaling data), the block decoder 160 may
perform trellis-decoding and block-decoding as inverse processes of the
transmitting system. On the other hand, if the data channel-equalized by
the equalizer 140 and inputted to the block decoder 160 correspond to
data processed only with trellis-encoding and not block-encoding by the
transmitting system (i.e., main service data), the block decoder 160 may
perform only trellis-decoding.

[0056]The signaling decoder 190 decoded signaling data that have been
channel-equalized and inputted from the equalizer 140. It is assumed that
the signaling data inputted to the signaling decoder 190 correspond to
data processed with both block-encoding and trellis-encoding by the
transmitting system. Examples of such signaling data may include
transmission parameter channel (TPC) data and fast information channel
(FIC) data. Each type of data will be described in more detail in a later
process. The FIC data decoded by the signaling decoder 190 are outputted
to the FIC handler 215. And, the TPC data decoded by the signaling
decoder 190 are outputted to the TPC handler 214.

[0057]Meanwhile, according to the present invention, the transmitting
system uses RS frames by encoding units. Herein, the RS frame may be
divided into a primary RS frame and a secondary RS frame. However,
according to the embodiment of the present invention, the primary RS
frame and the secondary RS frame will be divided based upon the level of
importance of the corresponding data.

[0058]The primary RS frame decoder 170 receives the data outputted from
the block decoder 160. At this point, according to the embodiment of the
present invention, the primary RS frame decoder 170 receives only the
mobile service data that have been Reed-Solomon (RS)-encoded and/or
cyclic redundancy check (CRC)-encoded from the block decoder 160. Herein,
the primary RS frame decoder 170 receives only the mobile service data
and not the main service data. The primary RS frame decoder 170 performs
inverse processes of an RS frame encoder (not shown) included in the
transmitting system, thereby correcting errors existing within the
primary RS frame. More specifically, the primary RS frame decoder 170
forms a primary RS frame by grouping a plurality of data groups and,
then, correct errors in primary RS frame units. In other words, the
primary RS frame decoder 170 decodes primary RS frames, which are being
transmitted for actual broadcast services.

[0059]Additionally, the secondary RS frame decoder 180 receives the data
outputted from the block decoder 160. At this point, according to the
embodiment of the present invention, the secondary RS frame decoder 180
receives only the mobile service data that have been RS-encoded and/or
CRC-encoded from the block decoder 160. Herein, the secondary RS frame
decoder 180 receives only the mobile service data and not the main
service data. The secondary RS frame decoder 180 performs inverse
processes of an RS frame encoder (not shown) included in the transmitting
system, thereby correcting errors existing within the secondary RS frame.
More specifically, the secondary RS frame decoder 180 forms a secondary
RS frame by grouping a plurality of data groups and, then, correct errors
in secondary RS frame units. In other words, the secondary RS frame
decoder 180 decodes secondary RS frames, which are being transmitted for
mobile audio service data, mobile video service data, guide data, and so
on.

[0060]Meanwhile, the management processor 200 according to an embodiment
of the present invention includes an MH physical adaptation processor
210, an IP network stack 220, a streaming handler 230, a system
information (SI) handler 240, a file handler 250, a multi-purpose
internet main extensions (MIME) type handler 260, and an electronic
service guide (ESG) handler 270, and an ESG decoder 280, and a storage
unit 290.

[0062]The TPC handler 214 receives and processes baseband information
required by modules corresponding to the MH physical adaptation processor
210. The baseband information is inputted in the form of TPC data.
Herein, the TPC handler 214 uses this information to process the FIC
data, which have been sent from the baseband processor 100.

[0063]The TPC data are transmitted from the transmitting system to the
receiving system via a predetermined region of a data group. The TPC data
may include at least one of an MH ensemble ID, an MH sub-frame number, a
total number of MH groups (TNoG), an RS frame continuity counter, a
column size of RS frame (N), and an FIC version number.

[0064]Herein, the MH ensemble ID indicates an identification number of
each MH ensemble carried in the corresponding channel.

[0065]The MH sub-frame number signifies a number identifying the MH
sub-frame number in an MH frame, wherein each MH group associated with
the corresponding MH ensemble is transmitted.

[0066]The TNoG represents the total number of MH groups including all of
the MH groups belonging to all MH parades included in an MH sub-frame.

[0067]The RS frame continuity counter indicates a number that serves as a
continuity counter of the RS frames carrying the corresponding MH
ensemble. Herein, the value of the RS frame continuity counter shall be
incremented by 1 module 16 for each successive RS frame.

[0068]N represents the column size of an RS frame belonging to the
corresponding MH ensemble. Herein, the value of N determines the size of
each MH TP.

[0069]Finally, the FIC version number signifies the version number of an
FIC carried on the corresponding physical channel.

[0070]As described above, diverse TPC data are inputted to the TPC handler
214 via the signaling decoder 190 shown in FIG. 1. Then, the received TPC
data are processed by the TPC handler 214. The received TPC data may also
be used by the FIC handler 215 in order to process the FIC data.

[0071]The FIC handler 215 processes the FIC data by associating the FIC
data received from the baseband processor 100 with the TPC data.

[0075]The MH transport packet (TP) handler 213 extracts a header from each
MH TP received from the primary RS frame handler 211 and the secondary RS
frame handler 212, thereby determining the data included in the
corresponding MH TP. Then, when the determined data correspond to SI data
(i.e., SI data that are not encapsulated to IP datagrams), the
corresponding data are outputted to the physical adaptation control
signal handler 216. Alternatively, when the determined data correspond to
an IP datagram, the corresponding data are outputted to the IP network
stack 220.

[0076]The IP network stack 220 processes broadcast data that are being
transmitted in the form of IP datagrams. More specifically, the IP
network stack 220 processes data that are inputted via user datagram
protocol (UDP), real-time transport protocol (RTP), real-time transport
control protocol (RTCP), asynchronous layered coding/layered coding
transport (ALC/LCT), file delivery over unidirectional transport (FLUTE),
and so on. Herein, when the processed data correspond to streaming data,
the corresponding data are outputted to the streaming handler 230. And,
when the processed data correspond to data in a file format, the
corresponding data are outputted to the file handler 250. Finally, when
the processed data correspond to SI-associated data, the corresponding
data are outputted to the SI handler 240.

[0077]The SI handler 240 receives and processes SI data having the form of
IP datagrams, which are inputted to the IP network stack 220.

[0078]When the inputted data associated with SI correspond to MIME-type
data, the inputted data are outputted to the MIME-type handler 260.

[0080]The file handler 250 receives data from the IP network stack 220 in
an object format in accordance with the ALC/LCT and FLUTE structures. The
file handler 250 groups the received data to create a file format.
Herein, when the corresponding file includes ESG, the file is outputted
to the ESG handler 270. On the other hand, when the corresponding file
includes data for other file-based services, the file is outputted to the
presentation controller 330 of the presentation processor 300.

[0081]The ESG handler 270 processes the ESG data received from the file
handler 250 and stores the processed ESG data to the storage unit 290.
Alternatively, the ESG handler 270 may output the processed ESG data to
the ESG decoder 280, thereby allowing the ESG data to be used by the ESG
decoder 280.

[0082]The storage unit 290 stores the system information (SI) received
from the physical adaptation control signal handler 210 and the ESG
handler 270 therein. Thereafter, the storage unit 290 transmits the
stored SI data to each block.

[0083]The ESG decoder 280 either recovers the ESG data and SI data stored
in the storage unit 290 or recovers the ESG data transmitted from the ESG
handler 270. Then, the ESG decoder 280 outputs the recovered data to the
presentation controller 330 in a format that can be outputted to the
user.

[0084]The streaming handler 230 receives data from the IP network stack
220, wherein the format of the received data are in accordance with RTP
and/or RTCP structures. The streaming handler 230 extracts audio/video
streams from the received data, which are then outputted to the
audio/video (A/V) decoder 310 of the presentation processor 300. The
audio/video decoder 310 then decodes each of the audio stream and video
stream received from the streaming handler 230.

[0085]The display module 320 of the presentation processor 300 receives
audio and video signals respectively decoded by the A/V decoder 310.
Then, the display module 320 provides the received audio and video
signals to the user through a speaker and/or a screen.

[0086]The presentation controller 330 corresponds to a controller managing
modules that output data received by the receiving system to the user.

[0087]The channel service manager 340 manages an interface with the user,
which enables the user to use channel-based broadcast services, such as
channel map management, channel service connection, and so on.

[0088]The application manager 350 manages an interface with a user using
ESG display or other application services that do not correspond to
channel-based services.

[0089]Data Format Structure

[0090]Meanwhile, the data structure used in the mobile broadcasting
technology according to the embodiment of the present invention may
include a data group structure and an RS frame structure, which will now
be described in detail.

[0091]FIG. 2 illustrates an exemplary structure of a data group according
to the present invention.

[0092]FIG. 2 shows an example of dividing a data group according to the
data structure of the present invention into 10 MH blocks (i.e., MH block
1 (B1) to MH block 10 (B10)). In this example, each MH block has the
length of 16 segments. Referring to FIG. 2, only the RS parity data are
allocated to portions of the previous 5 segments of the MH block 1 (B1)
and the next 5 segments of the MH block 10 (B10). The RS parity data are
excluded in regions A to D of the data group.

[0093]More specifically, when it is assumed that one data group is divided
into regions A, B, C, and D, each MH block may be included in any one of
region A to region D depending upon the characteristic of each MH block
within the data group. Herein, the data group is divided into a plurality
of regions to be used for different purposes. More specifically, a region
of the main service data having no interference or a very low
interference level may be considered to have a more resistant (or
stronger) receiving performance as compared to regions having higher
interference levels. Additionally, when using a system inserting and
transmitting known data in the data group, wherein the known data are
known based upon an agreement between the transmitting system and the
receiving system, and when consecutively long known data are to be
periodically inserted in the mobile service data, the known data having a
predetermined length may be periodically inserted in the region having no
interference from the main service data (i.e., a region wherein the main
service data are not mixed). However, due to interference from the main
service data, it is difficult to periodically insert known data and also
to insert consecutively long known data to a region having interference
from the main service data.

[0094]Referring to FIG. 2, MH block 4 (B4) to MH block 7 (B7) correspond
to regions without interference of the main service data. MH block 4 (B4)
to MH block 7 (B7) within the data group shown in FIG. 2 correspond to a
region where no interference from the main service data occurs. In this
example, a long known data sequence is inserted at both the beginning and
end of each MH block. In the description of the present invention, the
region including MH block 4 (B4) to MH block 7 (B7) will be referred to
as "region A (=B4+B5+B6+B7)". As described above, when the data group
includes region A having a long known data sequence inserted at both the
beginning and end of each MH block, the receiving system is capable of
performing equalization by using the channel information that can be
obtained from the known data. Therefore, the strongest equalizing
performance may be yielded (or obtained) from one of region A to region
D.

[0095]In the example of the data group shown in FIG. 2, MH block (B3) and
MH block 8 (B8) correspond to a region having little interference from
the main service data. Herein, a long known data sequence is inserted in
only one side of each MH block B3 and B8. More specifically, due to the
interference from the main service data, a long known data sequence is
inserted at the end of MH block 3 (B3), and another long known data
sequence is inserted at the beginning of MH block 8 (B8). In the present
invention, the region including MH block 3 (B3) and MH block 8 (B8) will
be referred to as "region B (=B3+B8)". As described above, when the data
group includes region B having a long known data sequence inserted at
only one side (beginning or end) of each MH block, the receiving system
is capable of performing equalization by using the channel information
that can be obtained from the known data. Therefore, a stronger
equalizing performance as compared to region C/D may be yielded (or
obtained).

[0096]Referring to FIG. 2, MH block 2 (B2) and MH block 9 (B9) correspond
to a region having more interference from the main service data as
compared to region B. A long known data sequence cannot be inserted in
any side of MH block 2 (B2) and MH block 9 (B9). Herein, the region
including MH block 2 (B2) and MH block 9 (B9) will be referred to as
"region C (=B2+B9)".

[0097]Finally, in the example shown in FIG. 2, MH block 1 (B1) and MH
block 10 (B10) correspond to a region having more interference from the
main service data as compared to region C. Similarly, a long known data
sequence cannot be inserted in any side of MH block 1 (B1) and MH block
10 (B10). Herein, the region including MH block 1 (B1) and MH block 10
(B10) will be referred to as "region D (=B1+B10)". Since region C/D is
spaced further apart from the known data sequence, when the channel
environment undergoes frequent and abrupt changes, the receiving
performance of region C/D may be deteriorated.

[0098]Additionally, the data group includes a signaling information area
wherein signaling information is assigned (or allocated).

[0099]In the present invention, the signaling information area may start
from the 1st segment of the 4th MH block (B4) to a portion of
the 2nd segment. According to an embodiment of the present
invention, the signaling information area for inserting signaling
information may start from the 1st segment of the 4th MH block
(B4) to a portion of the 2nd segment.

[0100]More specifically, 276(=207+69) bytes of the 4th MH block (B4)
in each data group are assigned as the signaling information area. In
other words, the signaling information area consists of 207 bytes of the
1st segment and the first 69 bytes of the 2nd segment of the
4th MH block (B4). The 1st segment of the 4th MH block
(B4) corresponds to the 17th or 173rd segment of a VSB field.

[0101]Herein, the signaling information may be identified by two different
types of signaling channels: a transmission parameter channel (TPC) and a
fast information channel (FIC).

[0102]Herein, the TPC data may include at least one of an MH ensemble ID,
an MH sub-frame number, a total number of MH groups (TNoG), an RS frame
continuity counter, a column size of RS frame (N), and an FIC version
number. However, the TPC data (or information) presented herein are
merely exemplary. And, since the adding or deleting of signaling
information included in the TPC data may be easily adjusted and modified
by one skilled in the art, the present invention will, therefore, not be
limited to the examples set forth herein. Furthermore, the FIC is
provided to enable a fast service acquisition of data receivers, and the
FIC includes cross layer information between the physical layer and the
upper layer(s).

[0103]For example, when the data group includes 6 known data sequences, as
shown in FIG. 2, the signaling information area is located between the
first known data sequence and the second known data sequence. More
specifically, the first known data sequence is inserted in the last 2
segments of the 3rd MH block (B3), and the second known data
sequence in inserted in the 2nd and 3rd segments of the
4th MH block (B4). Furthermore, the 3rd to 6th known data
sequences are respectively inserted in the last 2 segments of each of the
4th, 5th, 6th, and 7th MH blocks (B4, B5, B6, and
B7). The 1st and 3rd to 6th known data sequences are
spaced apart by 16 segments.

[0104]FIG. 3 illustrates an RS frame according to an embodiment of the
present invention.

[0105]The RS frame shown in FIG. 3 corresponds to a collection of one or
more data groups. The RS frame is received for each MH frame in a
condition where the receiving system receives the FIC and processes the
received FIC and where the receiving system is switched to a time-slicing
mode so that the receiving system can receive MH ensembles including ESG
entry points. Each RS frame includes IP streams of each service or ESG,
and SMT section data may exist in all RS frames.

[0106]The RS frame according to the embodiment of the present invention
consists of at least one MH transport packet (TP). Herein, the MH TP
includes an MH header and an MH payload.

[0107]The MH payload may include mobile service data as well as signaling
data. More specifically, an MH payload may include only mobile service
data, or may include only signaling data, or may include both mobile
service data and signaling data.

[0108]According to the embodiment of the present invention, the MH header
may identify (or distinguish) the data types included in the MH payload.
More specifically, when the MH TP includes a first MH header, this
indicates that the MH payload includes only the signaling data. Also,
when the MH TP includes a second MH header, this indicates that the MH
payload includes both the signaling data and the mobile service data.
Finally, when MH TP includes a third MH header, this indicates that the
MH payload includes only the mobile service data.

[0109]In the example shown in FIG. 3, the RS frame is assigned with IP
datagrams (IP datagram 1 and IP datagram 2) for two service types.

[0110]Data Transmission Structure

[0111]FIG. 4 illustrates a structure of a MH frame for transmitting and
receiving mobile service data according to the present invention. In the
example shown in FIG. 4, one MH frame consists of 5 sub-frames, wherein
each sub-frame includes 16 slots. In this case, the MH frame according to
the present invention includes 5 sub-frames and 80 slots.

[0112]Also, in a packet level, one slot is configured of 156 data packets
(i.e., transport stream packets), and in a symbol level, one slot is
configured of 156 data segments. Herein, the size of one slot corresponds
to one half (1/2) of a VSB field. More specifically, since one 207-byte
data packet has the same amount of data as a data segment, a data packet
prior to being interleaved may also be used as a data segment. At this
point, two VSB fields are grouped to form a VSB frame.

[0113]FIG. 5 illustrates an exemplary structure of a VSB frame, wherein
one VSB frame consists of 2 VSB fields (i.e., an odd field and an even
field). Herein, each VSB field includes a field synchronization segment
and 312 data segments.

[0114]The slot corresponds to a basic time unit for multiplexing the
mobile service data and the main service data. Herein, one slot may
either include the mobile service data or be configured only of the main
service data.

[0115]If the first 118 data packets within the slot correspond to a data
group, the remaining 38 data packets become the main service data
packets. In another example, when no data group exists in a slot, the
corresponding slot is configured of 156 main service data packets.

[0116]Meanwhile, when the slots are assigned to a VSB frame, an off-set
exists for each assigned position.

[0117]FIG. 6 illustrates a mapping example of the positions to which the
first 4 slots of a sub-frame are assigned with respect to a VSB frame in
a spatial area. And, FIG. 7 illustrates a mapping example of the
positions to which the first 4 slots of a sub-frame are assigned with
respect to a VSB frame in a chronological (or time) area.

[0118]Referring to FIG. 6 and FIG. 7, a 38th data packet (TS packet
#37) of a 1st slot (Slot #0) is mapped to the 1st data packet
of an odd VSB field. A 38th data packet (TS packet #37) of a
2nd slot (Slot #1) is mapped to the 157th data packet of an odd
VSB field. Also, a 38th data packet (TS packet #37) of a 3rd
slot (Slot #2) is mapped to the 1st data packet of an even VSB
field. And, a 38th data packet (TS packet #37) of a 4th slot
(Slot #3) is mapped to the 157th data packet of an even VSB field.
Similarly, the remaining 12 slots within the corresponding sub-frame are
mapped in the subsequent VSB frames using the same method.

[0119]FIG. 8 illustrates an exemplary assignment order of data groups
being assigned to one of 5 sub-frames, wherein the 5 sub-frames configure
an MH frame. For example, the method of assigning data groups may be
identically applied to all MH frames or differently applied to each MH
frame. Furthermore, the method of assigning data groups may be
identically applied to all sub-frames or differently applied to each
sub-frame. At this point, when it is assumed that the data groups are
assigned using the same method in all sub-frames of the corresponding MH
frame, the total number of data groups being assigned to an MH frame is
equal to a multiple of `5`.

[0120]According to the embodiment of the present invention, a plurality of
consecutive data groups is assigned to be spaced as far apart from one
another as possible within the sub-frame. Thus, the system can be capable
of responding promptly and effectively to any burst error that may occur
within a sub-frame.

[0121]For example, when it is assumed that 3 data groups are assigned to a
sub-frame, the data groups are assigned to a 1st slot (Slot #0), a
5th slot (Slot #4), and a 9th slot (Slot #8) in the sub-frame,
respectively. FIG. 8 illustrates an example of assigning 16 data groups
in one sub-frame using the above-described pattern (or rule). In other
words, each data group is serially assigned to 16 slots corresponding to
the following numbers: 0, 8, 4, 12, 1, 9, 5, 13, 2, 10, 6, 14, 3, 11, 7,
and 15. Equation 1 below shows the above-described rule (or pattern) for
assigning data groups in a sub-frame.

[0127]Herein, j indicates the slot number within a sub-frame. The value of
j may range from 0 to 15 (i.e., 0≦j≦15). Also, variable i
indicates the data group number. The value of i may range from 0 to 15
(i.e., 0≦i≦15).

[0128]In the present invention, a collection of data groups included in a
MH frame will be referred to as a "parade". Based upon the RS frame mode,
the parade transmits data of at least one specific RS frame.

[0129]The mobile service data within one RS frame may be assigned either
to all of regions A/B/C/D within the corresponding data group, or to at
least one of regions A/B/C/D. In the embodiment of the present invention,
the mobile service data within one RS frame may be assigned either to all
of regions A/B/C/D, or to at least one of regions A/B and regions C/D. If
the mobile service data are assigned to the latter case (i.e., one of
regions A/B and regions C/D), the RS frame being assigned to regions A/B
and the RS frame being assigned to regions C/D within the corresponding
data group are different from one another. According to the embodiment of
the present invention, the RS frame being assigned to regions A/B within
the corresponding data group will be referred to as a "primary RS frame",
and the RS frame being assigned to regions C/D within the corresponding
data group will be referred to as a "secondary RS frame", for simplicity.
Also, the primary RS frame and the secondary RS frame form (or configure)
one parade. More specifically, when the mobile service data within one RS
frame are assigned either to all of regions A/B/C/D within the
corresponding data group, one parade transmits one RS frame. Conversely,
when the mobile service data within one RS frame are assigned either to
at least one of regions A/B and regions C/D, one parade may transmit up
to 2 RS frames.

[0130]More specifically, the RS frame mode indicates whether a parade
transmits one RS frame, or whether the parade transmits two RS frames.
Such RS frame mode is transmitted as the above-described TPC data.

[0131]Table 1 below shows an example of the RS frame mode.

TABLE-US-00001
TABLE 1
RS frame
mode
(2 bits) Description
00 There is only one primary RS frame for
all group regions
01 There are two separate RS frames.
Primary RS frame for group regions A and B
Secondary RS frame for group regions C and D
10 Reserved
11 Reserved

[0132]Table 1 illustrates an example of allocating 2 bits in order to
indicate the RS frame mode. For example, referring to Table 1, when the
RS frame mode value is equal to `00`, this indicates that one parade
transmits one RS frame. And, when the RS frame mode value is equal to
`01`, this indicates that one parade transmits two RS frames, i.e., the
primary RS frame and the secondary RS frame. More specifically, when the
RS frame mode value is equal to `01`, data of the primary RS frame for
regions A/B are assigned and transmitted to regions A/B of the
corresponding data group. Similarly, data of the secondary RS frame for
regions C/D are assigned and transmitted to regions C/D of the
corresponding data group.

[0133]As described in the assignment of data groups, the parades are also
assigned to be spaced as far apart from one another as possible within
the sub-frame. Thus, the system can be capable of responding promptly and
effectively to any burst error that may occur within a sub-frame.

[0134]Furthermore, the method of assigning parades may be identically
applied to all MH frames or differently applied to each MH frame.
According to the embodiment of the present invention, the parades may be
assigned differently for each MH frame and identically for all sub-frames
within an MH frame. More specifically, the MH frame structure may vary by
MH frame units. Thus, an ensemble rate may be adjusted on a more frequent
and flexible basis.

[0135]FIG. 9 illustrates an example of multiple data groups of a single
parade being assigned (or allocated) to an MH frame. More specifically,
FIG. 9 illustrates an example of a plurality of data groups included in a
single parade, wherein the number of data groups included in a sub-frame
is equal to `3`, being allocated to an MH frame.

[0136]Referring to FIG. 9, 3 data groups are sequentially assigned to a
sub-frame at a cycle period of 4 slots. Accordingly, when this process is
equally performed in the 5 sub-frames included in the corresponding MH
frame, 15 data groups are assigned to a single MH frame. Herein, the 15
data groups correspond to data groups included in a parade. Therefore,
since one sub-frame is configured of 4 VSB frame, and since 3 data groups
are included in a sub-frame, the data group of the corresponding parade
is not assigned to one of the 4 VSB frames within a sub-frame.

[0137]For example, when it is assumed that one parade transmits one RS
frame, and that a RS frame encoder (not shown) included in the
transmitting system performs RS-encoding on the corresponding RS frame,
thereby adding 24 bytes of parity data to the corresponding RS frame and
transmitting the processed RS frame, the parity data occupy approximately
11.37% (=24/(187+24)×100) of the total code word length. Meanwhile,
when one sub-frame includes 3 data groups, and when the data groups
included in the parade are assigned, as shown in FIG. 9, a total of 15
data groups form an RS frame. Accordingly, even when an error occurs in
an entire data group due to a burst noise within a channel, the
percentile is merely 6.67% (= 1/15×100). Therefore, the receiving
system may correct all errors by performing an erasure RS decoding
process. More specifically, when the erasure RS decoding is performed, a
number of channel errors corresponding to the number of RS parity bytes
may be corrected. By doing so, the receiving system may correct the error
of at least one data group within one parade. Thus, the minimum burst
noise length correctable by a RS frame is over 1 VSB frame.

[0138]Meanwhile, when data groups of a parade are assigned as shown in
FIG. 9, either main service data may be assigned between each data group,
or data groups corresponding to different parades may be assigned between
each data group. More specifically, data groups corresponding to multiple
parades may be assigned to one MH frame.

[0139]Basically, the method of assigning data groups corresponding to
multiple parades is very similar to the method of assigning data groups
corresponding to a single parade. In other words, data groups included in
other parades that are to be assigned to an MH frame are also
respectively assigned according to a cycle period of 4 slots.

[0140]At this point, data groups of a different parade may be sequentially
assigned to the respective slots in a circular method. Herein, the data
groups are assigned to slots starting from the ones to which data groups
of the previous parade have not yet been assigned.

[0141]For example, when it is assumed that data groups corresponding to a
parade are assigned as shown in FIG. 9, data groups corresponding to the
next parade may be assigned to a sub-frame starting either from the
12th slot of a sub-frame. However, this is merely exemplary. In
another example, the data groups of the next parade may also be
sequentially assigned to a different slot within a sub-frame at a cycle
period of 4 slots starting from the 3rd slot.

[0142]FIG. 10 illustrates an example of transmitting 3 parades (Parade #0,
Parade #1, and Parade #2) to an MH frame. More specifically, FIG. 10
illustrates an example of transmitting parades included in one of 5
sub-frames, wherein the 5 sub-frames configure one MH frame.

[0143]When the 1st parade (Parade #0) includes 3 data groups for each
sub-frame, the positions of each data groups within the sub-frames may be
obtained by substituting values `0` to `2` for i in Equation 1. More
specifically, the data groups of the 1st parade (Parade #0) are
sequentially assigned to the 1st, 5th, and 9th slots (Slot
#0, Slot #4, and Slot #8) within the sub-frame.

[0144]Also, when the 2nd parade includes 2 data groups for each
sub-frame, the positions of each data groups within the sub-frames may be
obtained by substituting values `3` and `4` for in Equation 1. More
specifically, the data groups of the 2nd parade (Parade #1) are
sequentially assigned to the 2nd and 12th slots (Slot #1 and
Slot #11) within the sub-frame.

[0145]Finally, when the 3rd parade includes 2 data groups for each
sub-frame, the positions of each data groups within the sub-frames may be
obtained by substituting values `5` and `6` for i in Equation 1. More
specifically, the data groups of the 3rd parade (Parade #2) are
sequentially assigned to the 7th and 11th slots (Slot #6 and
Slot #10) within the sub-frame.

[0146]As described above, data groups of multiple parades may be assigned
to a single MH frame, and, in each sub-frame, the data groups are
serially allocated to a group space having 4 slots from left to right.

[0147]Therefore, a number of groups of one parade per sub-frame (NoG) may
correspond to any one integer from `1` to `8`. Herein, since one MH frame
includes 5 sub-frames, the total number of data groups within a parade
that can be allocated to an MH frame may correspond to any one multiple
of `5` ranging from `5` to `40`.

[0148]FIG. 11 illustrates an example of expanding the assignment process
of 3 parades, shown in FIG. 10, to 5 sub-frames within an MH frame.

[0149]FIG. 12 illustrates a data transmission structure according to an
embodiment of the present invention, wherein signaling data are included
in a data group so as to be transmitted.

[0150]As described above, an MH frame is divided into 5 sub-frames. Data
groups corresponding to a plurality of parades co-exist in each
sub-frame. Herein, the data groups corresponding to each parade are
grouped by MH frame units, thereby configuring a single parade.

[0151]The data structure shown in FIG. 12 includes 3 parades, one ESG
dedicated channel (EDC) parade (i.e., parade with NoG=1), and 2 service
parades (i.e., parade with NoG=4 and parade with NoG=3). Also, a
predetermined portion of each data group (i.e., 37 bytes/data group) is
used for delivering (or sending) FIC information associated with mobile
service data, wherein the FIC information is separately encoded from the
RS-encoding process. The FIC region assigned to each data group consists
of one FIC segments. Herein, each segment is interleaved by MH sub-frame
units, thereby configuring an FIC body, which corresponds to a completed
FIC transmission structure. However, whenever required, each segment may
be interleaved by MH frame units and not by MH sub-frame units, thereby
being completed in MH frame units.

[0152]Meanwhile, the concept of an MH ensemble is applied in the
embodiment of the present invention, thereby defining a collection (or
group) of services. Each MH ensemble carries the same QoS and is coded
with the same FEC code. Also, each MH ensemble has the same unique
identifier (i.e., ensemble ID) and corresponds to consecutive RS frames.

[0153]As shown in FIG. 12, the FIC segment corresponding to each data
group described service information of an MH ensemble to which the
corresponding data group belongs. When FIC segments within a sub-frame
are grouped and deinterleaved, all service information of a physical
channel through which the corresponding FICs are transmitted may be
obtained. Therefore, the receiving system may be able to acquire the
channel information of the corresponding physical channel, after being
processed with physical channel tuning, during a sub-frame period.

[0154]Furthermore, FIG. 12 illustrates a structure further including a
separate EDC parade apart from the service parade and wherein electronic
service guide (ESG) data are transmitted in the 1st slot of each
sub-frame.

[0155]Hierarchical Signaling Structure

[0156]FIG. 13 illustrates a hierarchical signaling structure according to
an embodiment of the present invention. As shown in FIG. 13, the mobile
broadcasting technology according to the embodiment of the present
invention adopts a signaling method using FIC and SMT. In the description
of the present invention, the signaling structure will be referred to as
a hierarchical signaling structure.

[0157]Hereinafter, a detailed description on how the receiving system
accesses a virtual channel via FIC and SMT will now be given with
reference to FIG. 13.

[0158]The FIC body defined in an MH transport (M1) identifies the physical
location of each the data stream for each virtual channel and provides
very high level descriptions of each virtual channel.

[0159]Being MH ensemble level signaling information, the service map table
(SMT) provides MH ensemble level signaling information. The SMT provides
the IP access information of each virtual channel belonging to the
respective MH ensemble within which the SMT is carried. The SMT also
provides all IP stream component level information required for the
virtual channel service acquisition.

[0161]The FIC body payload includes information on MH ensembles (e.g.,
ensemble_id field, and referred to as "ensemble location" in FIG. 13) and
information on a virtual channel associated with the corresponding MH
ensemble (e.g., when such information corresponds to a major_channel_num
field and a minor_channel_num field, the information is expressed as
Virtual Channel 0, Virtual Channel 1, . . . , Virtual Channel N in FIG.
13).

[0162]The application of the signaling structure in the receiving system
will now be described in detail.

[0163]When a user selects a channel he or she wishes to view (hereinafter,
the user-selected channel will be referred to as "channel θ" for
simplicity), the receiving system first parses the received FIC. Then,
the receiving system acquires information on an MH ensemble (i.e.,
ensemble location), which is associated with the virtual channel
corresponding to channel θ (hereinafter, the corresponding MH
ensemble will be referred to as "MH ensemble 0" for simplicity). By
acquiring slots only corresponding to the MH ensemble θ using the
time-slicing method, the receiving system configures ensemble θ.
The ensemble θ configured as described above, includes an SMT on
the associated virtual channels (including channel θ) and IP
streams on the corresponding virtual channels. Therefore, the receiving
system uses the SMT included in the MH ensemble θ in order to
acquire various information on channel θ (e.g., Virtual Channel
θ Table Entry) and stream access information on channel θ
(e.g., Virtual Channel θ Access Info). The receiving system uses
the stream access information on channel θ to receive only the
associated IP streams, thereby providing channel θ services to the
user.

[0164]Fast Information Channel (FIC)

[0165]The digital broadcast receiving system according to the present
invention adopts the fast information channel (FIC) for a faster access
to a service that is currently being broadcasted.

[0166]More specifically, the FIC handler 215 of FIG. 1 parses the FIC
body, which corresponds to an FIC transmission structure, and outputs the
parsed result to the physical adaptation control signal handler 216.

[0167]FIG. 14 illustrates an exemplary FIC body format according to an
embodiment of the present invention. According to the embodiment of the
present invention, the FIC format consists of an FIC body header and an
FIC body payload.

[0168]Meanwhile, according to the embodiment of the present invention,
data are transmitted through the FIC body header and the FIC body payload
in FIC segment units. Each FIC segment has the size of 37 bytes, and each
FIC segment consists of a 2-byte FIC segment header and a 35-byte FIC
segment payload. More specifically, an FIC body configured of an FIC body
header and an FIC body payload, is segmented in units of 35 data bytes,
which are then carried in at least one FIC segment within the FIC segment
payload, so as to be transmitted.

[0169]In the description of the present invention, an example of inserting
one FIC segment in one data group, which is then transmitted, will be
given. In this case, the receiving system receives a slot corresponding
to each data group by using a time-slicing method.

[0170]The signaling decoder 190 included in the receiving system shown in
FIG. 1 collects each FIC segment inserted in each data group. Then, the
signaling decoder 190 uses the collected FIC segments to created a single
FIC body. Thereafter, the signaling decoder 190 performs a decoding
process on the FIC body payload of the created FIC body, so that the
decoded FIC body payload corresponds to an encoded result of a signaling
encoder (not shown) included in the transmitting system. Subsequently,
the decoded FIC body payload is outputted to the FIC handler 215. The FIC
handler 215 parses the FIC data included in the FIC body payload, and
then outputs the parsed FIC data to the physical adaptation control
signal handler 216. The physical adaptation control signal handler 216
uses the inputted FIC data to perform processes associated with MH
ensembles, virtual channels, SMTs, and so on.

[0171]According to an embodiment of the present invention, when an FIC
body is segmented, and when the size of the last segmented portion is
smaller than 35 data bytes, it is assumed that the lacking number of data
bytes in the FIC segment payload is completed with by adding the same
number of stuffing bytes therein, so that the size of the last FIC
segment can be equal to 35 data bytes.

[0172]However, it is apparent that the above-described data byte values
(i.e., 37 bytes for the FIC segment, 2 bytes for the FIC segment header,
and 35 bytes for the FIC segment payload) are merely exemplary, and will,
therefore, not limit the scope of the present invention.

[0173]FIG. 15 illustrates an exemplary bit stream syntax structure with
respect to an FIC segment according to an embodiment of the present
invention.

[0174]Herein, the FIC segment signifies a unit used for transmitting the
FIC data. The FIC segment consists of an FIC segment header and an FIC
segment payload. Referring to FIG. 15, the FIC segment payload
corresponds to the portion starting from the `for` loop statement.
Meanwhile, the FIC segment header may include a FIC_type field, an
error_indicator field, an FIC_seg_number field, and an
FIC_last_seg_number field. A detailed description of each field will now
be given.

[0175]The FIC_type field is a 2-bit field indicating the type of the
corresponding FIC.

[0176]The error_indicator field is a 1-bit field, which indicates whether
or not an error has occurred within the FIC segment during data
transmission. If an error has occurred, the value of the error_indicator
field is set to `1`. More specifically, when an error that has failed to
be recovered still remains during the configuration process of the FIC
segment, the error_indicator field value is set to `1`. The
error_indicator field enables the receiving system to recognize the
presence of an error within the FIC data.

[0177]The FIC_seg_number field is a 4-bit field. Herein, when a single FIC
body is divided into a plurality of FIC segments and transmitted, the
FIC_seg_number field indicates the number of the corresponding FIC
segment.

[0178]Finally, the FIC_last_seg_number field is also a 4-bit field. The
FIC_last_seg_number field indicates the number of the last FIC segment
within the corresponding FIC body.

[0179]FIG. 16 illustrates an exemplary bit stream syntax structure with
respect to a payload of an FIC segment according to the present
invention, when an FIC_type field value is equal to `0`.

[0180]According to the embodiment of the present invention, the payload of
the FIC segment is divided into 3 different regions.

[0181]A first region of the FIC segment payload exists only when the
FIC_seg_number field value is equal to `0`. Herein, the first region may
include a current_next_indicator field, an ESG_version field, and a
transport_stream_id field. However, depending upon the embodiment of the
present invention, it may be assumed that each of the 3 fields exists
regardless of the FIC_seg_number field.

[0182]The current_next_indicator field is a 1-bit field. The
current_next_indicator field acts as an indicator identifying whether the
corresponding FIC data carry MH ensemble configuration information of an
MH frame including the current FIC segment, or whether the corresponding
FIC data carry MH ensemble configuration information of a next MH frame.

[0183]The ESG_version field is a 5-bit field indicating ESG version
information. Herein, by providing version information on the service
guide providing channel of the corresponding ESG, the ESG_version field
enables the receiving system to notify whether or not the corresponding
ESG has been updated.

[0184]Finally, the transport_stream_id field is a 16-bit field acting as a
unique identifier of a broadcast stream through which the corresponding
FIC segment is being transmitted.

[0185]A second region of the FIC segment payload corresponds to an
ensemble loop region, which includes an ensemble_id field, an SI_version
field, and a num_channel field.

[0186]More specifically, the ensemble_id field is an 8-bit field
indicating identifiers of an MH ensemble through which MH services are
transmitted. The MH services will be described in more detail in a later
process. Herein, the ensemble_id field binds the MH services and the MH
ensemble.

[0187]The SI_version field is a 4-bit field indicating version information
of SI data included in the corresponding ensemble, which is being
transmitted within the RS frame.

[0188]Finally, the num_channel field is an 8-bit field indicating the
number of virtual channel being transmitted via the corresponding
ensemble.

[0189]A third region of the FIC segment payload a channel loop region,
which includes a channel_type field, a channel_activity field, a
CA_indicator field, a stand_alone_service_indicator field, a
major_channel_num field, and a minor_channel_num field.

[0190]The channel_type field is a 5-bit field indicating a service type of
the corresponding virtual channel. For example, the channel_type field
may indicates an audio/video channel, an audio/video and data channel, an
audio-only channel, a data-only channel, a file download channel, an ESG
delivery channel, a notification channel, and so on.

[0191]The channel_activity field is a 2-bit field indicating activity
information of the corresponding virtual channel. More specifically, the
channel_activity field may indicate whether the current virtual channel
is providing the current service.

[0192]The CA_indicator field is a 1-bit field indicating whether or not a
conditional access (CA) is applied to the current virtual channel.

[0193]The stand_alone_service_indicator field is also a 1-bit field, which
indicates whether the service of the corresponding virtual channel
corresponds to a stand alone service.

[0194]The major_channel_num field is an 8-bit field indicating a major
channel number of the corresponding virtual channel.

[0195]Finally, the minor_channel_num field is also an 8-bit field
indicating a minor channel number of the corresponding virtual channel.

[0196]Service Table Map

[0197]FIG. 17 illustrates an exemplary bit stream syntax structure of a
service map table (hereinafter referred to as "SMT") according to the
present invention.

[0198]According to the embodiment of the present invention, the SMT is
configured in an MPEG-2 private section format. However, this will not
limit the scope and spirit of the present invention. The SMT according to
the embodiment of the present invention includes description information
for each virtual channel within a single MH ensemble. And, additional
information may further be included in each descriptor area.

[0199]Herein, the SMT according to the embodiment of the present invention
includes at least one field and is transmitted from the transmitting
system to the receiving system.

[0200]As described in FIG. 3, the SMT section may be transmitted by being
included in the MH TP within the RS frame. In this case, each of the RS
frame decoders 170 and 180, shown in FIG. 1, decodes the inputted RS
frame, respectively. Then, each of the decoded RS frames is outputted to
the respective RS frame handler 211 and 212. Thereafter, each RS frame
handler 211 and 212 identifies the inputted RS frame by row units, so as
to create an MH TP, thereby outputting the created MH TP to the MH TP
handler 213.

[0201]When it is determined that the corresponding MH TP includes an SMT
section based upon the header in each of the inputted MH TP, the MH TP
handler 213 parses the corresponding SMT section, so as to output the SI
data within the parsed SMT section to the physical adaptation control
signal handler 216. However, this is limited to when the SMT is not
encapsulated to IP datagrams.

[0202]Meanwhile, when the SMT is encapsulated to IP datagrams, and when it
is determined that the corresponding MH TP includes an SMT section based
upon the header in each of the inputted MH TP, the MH TP handler 213
outputs the SMT section to the IP network stack 220. Accordingly, the IP
network stack 220 performs IP and UDP processes on the inputted SMT
section and, then, outputs the processed SMT section to the SI handler
240. The SI handler 240 parses the inputted SMT section and controls the
system so that the parsed SI data can be stored in the storage unit 290.

[0203]The following corresponds to example of the fields that may be
transmitted through the SMT.

[0204]A table_id field corresponds to an 8-bit unsigned integer number,
which indicates the type of table section. The table_id field allows the
corresponding table to be defined as the service map table (SMT).

[0205]An ensemble_id field is an 8-bit unsigned integer field, which
corresponds to an ID value associated to the corresponding MH ensemble.
Herein, the ensemble_id field may be assigned with a value ranging from
range `0x00` to `0x3F`. It is preferable that the value of the
ensemble_id field is derived from the parade_id of the TPC data, which is
carried from the baseband processor of MH physical layer subsystem. When
the corresponding MH ensemble is transmitted through (or carried over)
the primary RS frame, a value of `0` may be used for the most significant
bit (MSB), and the remaining 7 bits are used as the parade_id value of
the associated MH parade (i.e., for the least significant 7 bits).
Alternatively, when the corresponding MH ensemble is transmitted through
(or carried over) the secondary RS frame, a value of `1` may be used for
the most significant bit (MSB).

[0206]A num_channels field is an 8-bit field, which specifies the number
of virtual channels in the corresponding SMT section.

[0207]Meanwhile, the SMT according to the embodiment of the present
invention provides information on a plurality of virtual channels using
the `for` loop statement.

[0208]A major_channel_num field corresponds to an 8-bit field, which
represents the major_channel_number associated with the corresponding
virtual channel. Herein, the major_channel_num field may be assigned with
a value ranging from `0x00` to `0xFF`.

[0209]A minor_channel_num field corresponds to an 8-bit field, which
represents the minor channel number associated with the corresponding
virtual channel. Herein, the minor_channel_num field may be assigned with
a value ranging from `0x00` to `0xFF`.

[0210]A short_channel_name field indicates the short name of the virtual
channel. The service id field is a 16-bit unsigned integer number (or
value), which identifies the virtual channel service.

[0211]A service_type field is a 6-bit enumerated type field, which
designates the type of service carried in the corresponding virtual
channel as defined in Table 2 below.

[0212]A virtual_channel_activity field is a 2-bit enumerated field
identifying the activity status of the corresponding virtual channel.
When the most significant bit (MSB) of the virtual_channel_activity field
is `1`, the virtual channel is active, and when the most significant bit
(MSB) of the virtual_channel_activity field is `0`, the virtual channel
is inactive. Also, when the least significant bit (LSB) of the
virtual_channel_activity field is `1`, the virtual channel is hidden
(when set to 1), and when the least significant bit (LSB) of the
virtual_channel_activity field is `0`, the virtual channel is not hidden.

[0213]A num_components field is a 5-bit field, which specifies the number
of IP stream components in the corresponding virtual channel.

[0214]An IP_version_flag field corresponds to a 1-bit indicator. More
specifically, when the value of the IP_version_flag field is set to `1`,
this indicates that a source_IP_address field, a
virtual_channel_target_IP_address field, and a
component_target_IP_address field are IPv6 addresses. Alternatively, when
the value of the IP_version_flag field is set to `0`, this indicates that
the source_IP_address field, the virtual_channel_target_IP_address field,
and the component_target_IP_address field are IPv4.

[0215]A source_IP_address_flag field is a 1-bit Boolean flag, which
indicates, when set, that a source IP address of the corresponding
virtual channel exist for a specific multicast source.

[0216]A virtual_channel_target_IP_address_flag field is a 1-bit Boolean
flag, which indicates, when set, that the corresponding IP stream
component is delivered through IP datagrams with target IP addresses
different from the virtual_channel_target_IP_address. Therefore, when the
flag is set, the receiving system (or receiver) uses the
component_target_IP_address as the target_IP_address in order to access
the corresponding IP stream component. Accordingly, the receiving system
(or receiver) may ignore the virtual_channel_target_IP_address field
included in the num_channels loop.

[0217]The source_IP_address field corresponds to a 32-bit or 128-bit
field. Herein, the source_IP_address field will be significant (or
present), when the value of the source_IP_address_flag field is set to
`1`. However, when the value of the source_IP_address_flag field is set
to `0`, the source_IP_address field will become insignificant (or
absent). More specifically, when the source_IP_address_flag field value
is set to `1`, and when the IP_version_flag field value is set to `0`,
the source_IP_address field indicates a 32-bit IPv4 address, which shows
the source of the corresponding virtual channel. Alternatively, when the
IP_version_flag field value is set to `1`, the source_IP_address field
indicates a 128-bit IPv6 address, which shows the source of the
corresponding virtual channel.

[0218]The virtual_channel_target_IP_address field also corresponds to a
32-bit or 128-bit field. Herein, the virtual_channel_target_IP_address
field will be significant (or present), when the value of the
virtual_channel_target_IP_address_flag field is set to `1`. However, when
the value of the virtual_channel_target_IP_address_flag field is set to
`0`, the virtual_channel_target_IP_address field will become
insignificant (or absent). More specifically, when the
virtual_channel_target_IP_address_flag field value is set to `1`, and
when the IP_version_flag field value is set to `0`, the
virtual_channel_target_IP_address field indicates a 32-bit target IPv4
address associated to the corresponding virtual channel. Alternatively,
when the virtual_channel_target_IP_address_flag field value is set to
`1`, and when the IP_version_flag field value is set to `1`, the
virtual_channel_target_IP_address field indicates a 64-bit target IPv6
address associated to the corresponding virtual channel. If the
virtual_channel_target_IP_address field is insignificant (or absent), the
component_target_IP_address field within the num_channels loop should
become significant (or present). And, in order to enable the receiving
system to access the IP stream component, the component_target_IP_address
field should be used.

[0219]Meanwhile, the SMT according to the embodiment of the present
invention uses a `for` loop statement in order to provide information on
a plurality of components.

[0220]Herein, an RTP_payload_type, which is assigned with 7 bits,
identifies the encoding format of the component based upon Table 3 shown
below. When the IP stream component is not encapsulated to RTP, the
RTP_payload_type shall be ignored (or deprecated).

[0222]For example, when the RTP_payload_type is assigned with a value of
`35`, this indicates that the corresponding IP stream component is a
video component encoded by an AVC method. Alternatively, when the
RTP_payload_type is assigned with a value of `36`, this indicates that
the corresponding IP stream component is an audio component encoded by an
MH method.

[0223]A component_target_IP_address_flag field is a 1-bit Boolean flag,
which indicates, when set, that the corresponding IP stream component is
delivered through IP datagrams with target IP addresses different from
the virtual_channel_target_IP_address. Furthermore, when the
component_target_IP_address_flag is set, the receiving system (or
receiver) uses the component_target_IP_address field as the target IP
address for accessing the corresponding IP stream component. Accordingly,
the receiving system (or receiver) will ignore the
virtual_channel_target_IP_address field included in the num channels
loop.

[0224]The component_target_IP_address field corresponds to a 32-bit or
128-bit field. Herein, when the value of the IP_version_flag field is set
to `0`, the component_target_IP_address field indicates a 32-bit target
IPv4 address associated to the corresponding IP stream component. And,
when the value of the IP_version_flag field is set to `1`, the
component_target_IP_address field indicates a 128-bit target IPv6 address
associated to the corresponding IP stream component.

[0225]A port_num_count field is a 6-bit field, which indicates the number
of UDP ports associated with the corresponding IP stream component. A
target UDP port number value starts from the target_UDP_port_num field
value and increases (or is incremented) by 1. For the RTP stream, the
target UDP port number should start from the target_UDP_port_num field
value and shall increase (or be incremented) by 2. This is to incorporate
RTCP streams associated with the RTP streams.

[0226]A target_UDP_port_num field is a 16-bit unsigned integer field,
which represents the target UDP port number for the corresponding IP
stream component. When used for RTP streams, the value of the
target_UDP_port_num field shall correspond to an even number. And, the
next higher value shall represent the target UDP port number of the
associated RTCP stream.

[0229]An ensemble_level_descriptor( ) represents zero or more descriptors
providing additional information for the MH ensemble, which is described
by the corresponding SMT.

[0230]FIG. 18 illustrates an exemplary bit stream syntax structure of an
MH audio descriptor according to the present invention.

[0231]When at least one audio service is present as a component of the
current event, the MH_audio_descriptor( ) shall be used as a
component_level_descriptor of the SMT. The MH_audio_descriptor( ) may be
capable of informing the system of the audio language type and stereo
mode status. If there is no audio service associated with the current
event, then it is preferable that the MH_audio_descriptor( ) is
considered to be insignificant (or absent) for the current event.

[0232]Each field shown in the bit stream syntax of FIG. 18 will now be
described in detail.

[0233]A descriptor_tag field is an 8-bit unsigned integer having a TBD
value, which indicates that the corresponding descriptor is the
MH_audio_descriptor( ).

[0234]A descriptor_length field is also an 8-bit unsigned integer, which
indicates the length (in bytes) of the portion immediately following the
descriptor_length field up to the end of the MH_audio_descriptor( ).

[0235]A channel_configuration field corresponds to an 8-bit field
indicating the number and configuration of audio channels. The values
ranging from `1` to `6` respectively indicate the number and
configuration of audio channels as given for "Default bit stream index
number" in Table 42 of ISO/IEC 13818-7:2006. All other values indicate
that the number and configuration of audio channels are undefined.

[0236]A sample_rate_code field is a 3-bit field, which indicates the
sample rate of the encoded audio data. Herein, the indication may
correspond to one specific sample rate, or may correspond to a set of
values that include the sample rate of the encoded audio data as defined
in Table A3.3 of ATSC A/52B.

[0237]A bit_rate_code field corresponds to a 6-bit field. Herein, among
the 6 bits, the lower 5 bits indicate a nominal bit rate. More
specifically, when the most significant bit (MSB) is `0`, the
corresponding bit rate is exact. On the other hand, when the most
significant bit (MSB) is `0`, the bit rate corresponds to an upper limit
as defined in Table A3.4 of ATSC A/53B.

[0238]An ISO--639_language_code field is a 24-bit (i.e., 3-byte)
field indicating the language used for the audio stream component, in
conformance with ISO 639.2/B [x]. When a specific language is not present
in the corresponding audio stream component, the value of each byte will
be set to `0x00`.

[0239]FIG. 19 illustrates an exemplary bit stream syntax structure of an
MH current event descriptor according to the present invention.

[0240]The MH_current_event_descriptor( ) shall be used as the
virtual_channel_level_descriptor( ) within the SMT. Herein, the
MH_current_event_descriptor( ) provides basic information on the current
event (e.g., the start time, duration, and title of the current event,
etc.), which is transmitted via the respective virtual channel.

[0241]The fields included in the MH_current_event_descriptor( ) will now
be described in detail.

[0242]A descriptor_tag field corresponds to an 8-bit unsigned integer
having the value TBD, which identifies the current descriptor as the
MH_current_event_descriptor( ).

[0243]A descriptor_length field also corresponds to an 8-bit unsigned
integer, which indicates the length (in bytes) of the portion immediately
following the descriptor_length_field up to the end of the
MH_current_event_descriptor( ).

[0244]A current_event_start_time field corresponds to a 32-bit unsigned
integer quantity. The current_event_start_time field represents the start
time of the current event and, more specifically, as the number of GPS
seconds since 00:00:00 UTC, Jan. 6, 1980.

[0245]A current_event_duration field corresponds to a 24-bit field.
Herein, the current_event_duration field indicates the duration of the
current event in hours, minutes, and seconds (wherein the format is in 6
digits, 4-bit BCD=24 bits).

[0246]A title_length field specifies the length (in bytes) of a
title_text_field. Herein, the value `0` indicates that there are no
titles existing for the corresponding event.

[0247]The title_text field indicates the title of the corresponding event
in event title in the format of a multiple string structure as defined in
ATSC A/65C [x].

[0248]FIG. 20 illustrates an exemplary bit stream syntax structure of an
MH next event descriptor according to the present invention.

[0249]The optional MH_next_event_descriptor( ) shall be used as the
virtual_channel_level_descriptor( ) within the SMT. Herein, the
MH_next_event_descriptor( ) provides basic information on the next event
(e.g., the start time, duration, and title of the next event, etc.),
which is transmitted via the respective virtual channel.

[0250]The fields included in the MH_next_event_descriptor( ) will now be
described in detail.

[0251]A descriptor_tag field corresponds to an 8-bit unsigned integer
having the value TBD, which identifies the current descriptor as the
MH_next_event_descriptor( ).

[0252]A descriptor_length field also corresponds to an 8-bit unsigned
integer, which indicates the length (in bytes) of the portion immediately
following the descriptor_length_field up to the end of the
MH_next_event_descriptor( ).

[0253]A next_event_start_time field corresponds to a 32-bit unsigned
integer quantity. The next_event_start_time field represents the start
time of the next event and, more specifically, as the number of GPS
seconds since 00:00:00 UTC, Jan. 6, 1980.

[0254]A next_event_duration field corresponds to a 24-bit field. Herein,
the next_event_duration field indicates the duration of the next event in
hours, minutes, and seconds (wherein the format is in 6 digits, 4-bit
BCD=24 bits).

[0255]A title_length field specifies the length (in bytes) of a
title_text_field. Herein, the value `0` indicates that there are no
titles existing for the corresponding event.

[0256]The title_text field indicates the title of the corresponding event
in event title in the format of a multiple string structure as defined in
ATSC A/65C [x].

[0257]FIG. 21 illustrates an exemplary bit stream syntax structure of an
MH system time descriptor according to the present invention.

[0258]The MH_system_time descriptor( ) shall be used as the
ensemble_level_descriptor( ) within the SMT. Herein, the MH_system_time
descriptor( ) provides information on current time and date. The
MH_system_time descriptor( ) also provides information on the time zone
in which the transmitting system (or transmitter) transmitting the
corresponding broadcast stream is located, while taking into
consideration the mobile/portable characteristics of the MH service data.

[0259]The fields included in the MH_system_time descriptor( ) will now be
described in detail.

[0260]A descriptor_tag field corresponds to an 8-bit unsigned integer
having the value TBD, which identifies the current descriptor as the
MH_system_time descriptor( ).

[0261]A descriptor_length field also corresponds to an 8-bit unsigned
integer, which indicates the length (in bytes) of the portion immediately
following the descriptor_length_field up to the end of the MH_system_time
descriptor( ).

[0262]A system_time field corresponds to a 32-bit unsigned integer
quantity. The system_time field represents the current system time and,
more specifically, as the number of GPS seconds since 00:00:00 UTC, Jan.
6, 1980.

[0263]A GPS_UTC_offset field corresponds to an 8-bit unsigned integer,
which defines the current offset in whole seconds between GPS and UTC
time standards. In order to convert GPS time to UTC time, the
GPS_UTC_offset is subtracted from GPS time. Whenever the International
Bureau of Weights and Measures decides that the current offset is too far
in error, an additional leap second may be added (or subtracted).
Accordingly, the GPS_UTC_offset field value will reflect the change.

[0264]A time_zone_offset_polarity field is a 1-bit field, which indicates
whether the time of the time zone, in which the broadcast station is
located, exceeds (or leads or is faster) or falls behind (or lags or is
slower) than the UTC time. When the value of the
time_zone_offset_polarity field is equal to `0`, this indicates that the
time on the current time zone exceeds the UTC time. Therefore, a
time_zone_offset field value is added to the UTC time value. Conversely,
when the value of the time_zone_offset_polarity field is equal to `1`,
this indicates that the time on the current time zone falls behind the
UTC time. Therefore, the time_zone_offset field value is subtracted from
the UTC time value.

[0265]The time_zone_offset field is a 31-bit unsigned integer quantity.
More specifically, the time_zone_offset field represents, in GPS seconds,
the time offset of the time zone in which the broadcast station is
located, when compared to the UTC time.

[0266]A daylight_savings field corresponds to a 16-bit field providing
information on the Summer Time (i.e., the Daylight Savings Time).

[0267]A time_zone field corresponds to a (5×8)-bit field indicating
the time zone, in which the transmitting system (or transmitter)
transmitting the corresponding broadcast stream is located.

[0268]FIG. 22 illustrates segmentation and encapsulation processes of a
service map table (SMT) according to the present invention.

[0269]According to the present invention, the SMT is encapsulated to UDP,
while including a target IP address and a target UDP port number within
the IP datagram. More specifically, the SMT is first segmented into a
predetermined number of sections, then encapsulated to a UDP header, and
finally encapsulated to an IP header.

[0270]In addition, the SMT section provides signaling information on all
virtual channel included in the MH ensemble including the corresponding
SMT section. At least one SMT section describing the MH ensemble is
included in each RS frame included in the corresponding MH ensemble.
Finally, each SMT section is identified by an ensemble_id included in
each section.

[0271]According to the embodiment of the present invention, by informing
the receiving system of the target IP address and target UDP port number,
the corresponding data (i.e., target IP address and target UDP port
number) may be parsed without having the receiving system to request for
other additional information.

[0272]FIG. 23 illustrates a flow chart for accessing a virtual channel
using FIC and SMT according to the present invention.

[0273]More specifically, a physical channel is tuned (S501). And, when it
is determined that an MH signal exists in the tuned physical channel
(S502), the corresponding MH signal is demodulated (S503). Additionally,
FIC segments are grouped from the demodulated MH signal in sub-frame
units (S504 and S505).

[0274]According to the embodiment of the present invention, an FIC segment
is inserted in a data group, so as to be transmitted. More specifically,
the FIC segment corresponding to each data group described service
information on the MH ensemble to which the corresponding data group
belongs. When the FIC segments are grouped in sub-frame units and, then,
deinterleaved, all service information on the physical channel through
which the corresponding FIC segment is transmitted may be acquired.
Therefore, after the tuning process, the receiving system may acquire
channel information on the corresponding physical channel during a
sub-frame period. Once the FIC segments are grouped, in s504 and s505, a
broadcast stream through which the corresponding FIC segment is being
transmitted is identified (S506). For example, the broadcast stream may
be identified by parsing the transport_stream_id field of the FIC body,
which is configured by grouping the FIC segments.

[0275]Furthermore, an ensemble identifier, a major channel number, a minor
channel number, channel type information, and so on, are extracted from
the FIC body (S507). And, by using the extracted ensemble information,
only the slots corresponding to the designated ensemble are acquired by
using the time-slicing method, so as to configure an ensemble (S508).

[0276]Subsequently, the RS frame corresponding to the designated ensemble
is decoded (S509), and an IP socket is opened for SMT reception (S510).

[0277]According to the example given in the embodiment of the present
invention, the SMT is encapsulated to UDP, while including a target IP
address and a target UDP port number within the IP datagram. More
specifically, the SMT is first segmented into a predetermined number of
sections, then encapsulated to a UDP header, and finally encapsulated to
an IP header. According to the embodiment of the present invention, by
informing the receiving system of the target IP address and target UDP
port number, the receiving system parses the SMT sections and the
descriptors of each SMT section without requesting for other additional
information (S511).

[0278]The SMT section provides signaling information on all virtual
channel included in the MH ensemble including the corresponding SMT
section. At least one SMT section describing the MH ensemble is included
in each RS frame included in the corresponding MH ensemble. Also, each
SMT section is identified by an ensemble_id included in each section.

[0279]Furthermore each SMT provides IP access information on each virtual
channel subordinate to the corresponding MH ensemble including each SMT.
Finally, the SMT provides IP stream component level information required
for the servicing of the corresponding virtual channel.

[0280]Therefore, by using the information parsed from the SMT, the IP
stream component belonging to the virtual channel requested for reception
may be accessed (S513). Accordingly, the service associated with the
corresponding virtual channel is provided to the user (S514).

[0281]Meanwhile, when the IP stream component is encapsulated to RTP and
then received, the RTP_payload_type within the SMT indicates the encoding
format of the IP stream, which is carried in the payload of the
corresponding RTP packet. At this point, when the value of the
RTP_payload_type is within the range of `35` to `72`, the encoding format
of the corresponding IP stream component may be known by referring only
the RTP_payload_type value. This is because the receiving system and
transmitting system are already informed of the significance of each
field value based upon an agreement between the receiving system and the
transmitting system.

[0282]For example, when the RTP_payload_type is assigned with a value of
`35`, this indicates that the corresponding IP stream component is a
video component encoded by an AVC method. Alternatively, when the
RTP_payload_type is assigned with a value of `36`, this indicates that
the corresponding IP stream component is an audio component encoded by an
MH method.

[0283]On the other hand, the RTP_payload_type may be assigned with one of
the values ranging from `96` to `127`. According to the present
invention, the value range from `96` to `127` is referred to a dynamic
range.

[0284]When the RTP_payload_type is assigned with any one value within the
dynamic range, the receiving system is unable to known the encoding
format of the corresponding IP stream component by referring only to the
RTP_payload_type field value.

[0285]In order to resolve this problem, when the RTP_payload_type is
assigned with a value within the dynamic range, the present invention
transmits encoding format information (or an encoding parameter)
corresponding to the respective the RTP_payload_type value.

[0286]In this example of the present invention, the encoding format
information is transmitted in the form of a descriptor. In order to
simplify the description of the present invention, the descriptor-type
encoding format information will be referred to as an RTP payload
descriptor MH RTP_payload_Descriptor( ). Herein, the RTP payload type
descriptor may be transmitted as any one of an ensemble level descriptor,
a virtual channel_level_descriptor, and a component_level_descriptor
within at least one table of the SMT. According to the embodiment of the
present invention, the RTP payload descriptor will be transmitted as the
component level descriptor.

[0287]Also, according to the embodiment of the present invention, the RTP
payload descriptor expresses (or describes) the encoding format
information of the corresponding IP stream component as a MIME type.
Therefore, the receiving system may be able to extract and analyze the
text-type encoding format information expressed as a MIME type.

[0288]FIG. 24 illustrates an exemplary bit stream syntax structure of an
MH RTP payload descriptor according to the present invention.

[0289]The MH_RTP_payload_descriptor( ) specifies the RTP payload type
(i.e., the encoding format of the IP component assigned to the payload).
Yet, the MH_RTP_payload_descriptor( ) exists (or is present) only when
the value of the RTP_payload_type included in the num_components loop of
the SMT is within the dynamic range (i.e., the range of `96` to `127`).
When present, the MH_RTP_payload_descriptor( ) shall be used as a
component_level_descriptor of the SMT. The MH_RTP_payload_descriptor
translates (or matches) a dynamic RTP_payload_type value into (or with) a
MIME type. Accordingly, the receiving system (or receiver) may collect
(or gather) the encoding format of the IP stream component, which is
encapsulated in RTP.

[0290]The fields included in the MH_RTP_payload_descriptor( ) will now be
described in detail.

[0291]A descriptor_tag field corresponds to an 8-bit unsigned integer
having the value TBD, which identifies the current descriptor as the
MH_RTP_payload_descriptor( ).

[0292]A descriptor_length field also corresponds to an 8-bit unsigned
integer, which indicates the length (in bytes) of the portion immediately
following the descriptor_length_field up to the end of the
MH_RTP_payload_descriptor( ).

[0293]An RTP_payload_type corresponds to a 7-bit field, which identifies
the encoding format of the IP stream component. Herein, the value of the
RTP_payload_type is in the dynamic range of `96` to `127`. Herein, the
RTP_payload_type of the MH_RTP_payload_descriptor( ) and the
RTP_payload_type field included in the num_components loop of the SMT is
assigned with the same value. More specifically, the value of the
RTP_payload_type included in the num_components loop of the SMT may be
used as link information for being mapped with the
MH_RTP_payload_descriptor( ).

[0294]An MIME_type_length field specifies the length (in bytes) of an
MIME_type field.

[0295]The MIME_type field indicates the MIME type corresponding to the
encoding format of the IP stream component, which is described by the
MH_RTP_payload_descriptor( ).

[0296]Hereinafter, the process of acquiring the encoding format of the IP
stream component RTP-packetized and received will be described in detail.

[0297]For example, when the SMT is encapsulated in an IP datagram, the MH
TP handler 213 determines based upon the header of each inputted MH TP
whether or not the corresponding MH TP includes an SMT section. Then,
when the MH TP handler 213 determines that the corresponding MH TP
includes an SMT section, the corresponding MH TP is outputted to the IP
network stack 220. Then, the IP network stack 220 performs IP and UDP
processes on the SMT section, thereby outputting the processed SMT
section to the SI handler 240. The SI handler 240 then parses the
inputted SMT section and controls the system so that the parsed SI is
stored in the storage unit 290.

[0298]At this point, when the value of the RTP_payload type field of the
SMT is within the range of `35` and `72`, the SI handler 240 stores the
encoding format respective of the corresponding RTP_payload_type value to
the storage unit 290. Herein, the encoding format information
corresponding to the respective values within the range of `35` and `72`
may already be stored in a table format within the storage unit 290 of
the receiving system. In this case, the encoding format information
respective of the corresponding RTP_payload_type value may be read from
the pre-formed table, so as to be linked with the corresponding IP stream
component and then stored in the storage unit 290.

[0299]Furthermore, when the value of the RTP_payload_type of the SMT is
within the range of `92` and `127`, the SI handler 240 parses the
MH_RTP_payload_descriptor( ) which is received as the component level
descriptor of the SMT, thereby outputting the MIME_type( ) field value to
the MIME handler 260. Herein, the MIME_type( ) field is received by being
repeated as many times as the length of the MIME_type_length field.
Thereafter, the MIME handler 260 parses the MIME_type field, so as to
acquire the encoding format (or encoding parameter) respective of the
corresponding IP stream component. Herein, the encoding format respective
of the corresponding IP stream component is written in a text format. The
MIME handler 260 outputs the acquired encoding format respective of the
corresponding IP stream component to the SI handler 240. Subsequently,
the SI handler 240 either stores the encoding format respective of the
corresponding IP stream component to the storage unit 290 or outputs the
encoding format respective of the corresponding IP stream component to
the A/V decoder 310.

[0300]FIG. 25 illustrates an exemplary method for accessing an IP stream
component based upon an RTP payload according to an embodiment of the
present invention. More specifically, the SMT is parsed (S801), so as to
extract the RTP_payload_type value of the SMT (S802). Then, it is
determined whether or not the RTP_payload_type value is assigned with a
value within the range of `35` and `72` (S803). If it is determine that
the RTP_payload_type value is assigned with any one of the values ranging
from `35` to `72`, the encoding format respective of the corresponding
value is either stored in the storage unit 290 or outputted to the A/V
decoder 310 (S804). Herein, it is assumed that the receiving system is
pre-informed of the definition of the encoding format corresponding to a
value within the range of `35` and `72`.

[0301]However, when it is determined that the RTP_payload_type field value
is not within the range of `35` and `72`, it is then determined whether
or not the RTP_payload_type value is within the dynamic range (i.e.,
within the range of `92` to `127`) (S805). If the RTP_payload_type value
is not within the range of `92` to `127`, the RTP_payload_type determined
to be assigned with an undefined value. Therefore, an error message is
displayed (S806). Alternatively, if the RTP_payload_type value is within
the dynamic range of `92` to `127`, the MH_RTP_payload_descriptor( )
which is received as the component level descriptor of the SMT, is parsed
(S807). Then, the value of the MIME_type( ) field of the
MH_RTP_payload_descriptor( ) is parsed, so as to acquire the encoding
format (or encoding parameter) respective of the corresponding IP stream
component (S808). Herein, the MIME_type( ) field is received by being
repeated as many times as the length of the MIME_type_length field.

[0302]When the encoding format respective of the IP stream component is
acquired, it is determined whether or not the IP stream component is
decodable (S809). When it is determined, in step 809, that the IP stream
component is not decodable, an appropriate message is displayed (S810).
Conversely, when it is determined, in step 809, that the IP stream
component is decodable, the corresponding IP stream component is
accessed, and reference is made to the encoding format information
extracted in any one of step 804 and step 808 in order to perform a
decoding process on the accessed IP stream component (S811).

[0303]As described above, the digital broadcasting system and the data
processing method according to the present invention have the following
advantages. The present invention provides information on an encoding
parameter (i.e., encoding format information) of each IP stream component
within the corresponding virtual channel using the service map table
(SMT). Most particularly, the present invention may also provide encoding
format information of an IP stream component, which is not defined by the
digital broadcast receiving and transmitting system, using an RTP payload
descriptor of the corresponding SMT. At this point, the RTP payload type
descriptor may map an RTP_payload_type value within a dynamic range to
the encoding format information of the IP stream component expressed as a
MIME_type.

[0304]It will be apparent to those skilled in the art that various
modifications and variations can be made in the present invention without
departing from the spirit or scope of the inventions. Thus, it is
intended that the present invention covers the modifications and
variations of this invention provided they come within the scope of the
appended claims and their equivalents.